From 0384e3d5dfe16f87e40f948ee42e4697ed7442b6 Mon Sep 17 00:00:00 2001 From: Rostislav Pehlivanov Date: Fri, 12 Feb 2016 16:49:24 +0000 Subject: [PATCH] doc/encoders: add documentation for the VC-2 encoder Signed-off-by: Rostislav Pehlivanov --- doc/encoders.texi | 65 +++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 65 insertions(+) diff --git a/doc/encoders.texi b/doc/encoders.texi index e9311eb432..d854f1e2e6 100644 --- a/doc/encoders.texi +++ b/doc/encoders.texi @@ -2521,6 +2521,71 @@ encoder use CAVLC instead of CABAC. @end itemize +@section vc2 + +SMPTE VC-2 (previously BBC Dirac Pro). This codec was primarily aimed at +professional broadcasting but since it supports yuv420, yuv422 and yuv444 at +8 (limited range or full range), 10 or 12 bits, this makes it suitable for +other tasts which require low overhead and low compression (like screen +recording). + +@subsection Options + +@table @option + +@item b +Sets target video bitrate. Usually that's around 1:6 of the uncompressed +video bitrate (e.g. for 1920x1080 50fps yuv422p10 that's around 400Mbps). Higher +values (close to the uncompressed bitrate) turn on lossless compression mode. + +@item field_order +Enables field coding when set (e.g. to tt - top field first) for interlaced +inputs. Should increase compression with interlaced content as it splits the +fields and encodes each separately. + +@item wavelet_depth +Sets the total amount of wavelet transforms to apply, between 1 and 5 (default). +Lower values reduce compression and quality. Less capable decoders may not be +able to handle values of @option{wavelet_depth} over 3. + +@item wavelet_type +Sets the transform type. Currently only @var{5_3} (LeGall) and @var{9_7} +(Deslauriers-Dubuc) +are implemented, with 9_7 being the one with better compression and thus +is the default. + +@item slice_width +@item slice_height +Sets the slice size for each slice. Larger values result in better compression. +For compatibility with other more limited decoders use @option{slice_width} of +32 and @option{slice_height} of 8. + +@item tolerance +Sets the undershoot tolerance of the rate control system in percent. This is +to prevent an expensive search from being run. + +@item qm +Sets the quantization matrix preset to use by default or when @option{wavelet_depth} +is set to 5 +@itemize @minus +@item +@var{default} +Uses the default quantization matrix from the specifications, extended with +values for the fifth level. This provides a good balance between keeping detail +and omitting artifacts. + +@item +@var{flat} +Use a completely zeroed out quantization matrix. This increases PSNR but might +reduce perception. Use in bogus benchmarks. + +@item +@var{color} +Reduces detail but attempts to preserver color at extremely low bitrates. +@end itemize + +@end table + @c man end VIDEO ENCODERS @chapter Subtitles Encoders